6gt with accurate 1680

Durdy1

FNG
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Dec 22, 2025
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Ok 6gt guys. I am having a barrel spun up probably 17 inch. I have a couple lbs of accurate 1680. Would I be able to use this powder with Berger 105 for 200 rnds of barrel break in? If so what would be a starting charge weight. Just want to use up so older powder. Also. I have a defiance action. Do I really have to change firing pin hole and get it sleeved? If that is the correct word.

Thanks
 
Ok 6gt guys. I am having a barrel spun up probably 17 inch. I have a couple lbs of accurate 1680. Would I be able to use this powder with Berger 105 for 200 rnds of barrel break in? If so what would be a starting charge weight. Just want to use up so older powder. Also. I have a defiance action. Do I really have to change firing pin hole and get it sleeved? If that is the correct word.

Thanks
1680 is a bit fast for that use. Why not use it someplace where it’s a better fit? It’s really a magnum pistol/straightwall powder or 300 bo.
 
Fair enough. Like I said, just hoping to use it up, but maybe I will try to run it in the 350 legend. Thanks
 
Might be a off-topic question, but I am wanting to build a PRS rifle, and the favorites I have see listed (that have good supply of components available). Ever since I heard about the 6GT, I have been intrigued! But I also want to give the future rifle, my due diligence! So I am also comparing with the 6 CM and the 25 CM. Between the two Creedmoor's the 6CM seems to be leading, because of recoil, factory ammo & component availability. However, the 6GT, seems to be the new kid on the block, but things look favorable. I see that Hornady has released a match round for the 6GT, so far thats the only ballistics data I seen. I also seen that people complain that the 6CM is a barrel burner (but what I seen, its only about 200-400 rounds difference, when compared with the 6GT. Can someone help fill in the holes in my data. Any real world experience comparing the 6CM vs 6GT? I like the idea of 6CM ammo available, but unfortunately cannot find any 6GT locally. I must rely on factory ammo for a while until I can buy my reloading equipment (again). Thank you.
 
1680 sounds like a bad idea. Sorry.
I’ve used quite a bit of it when I loaded 762x39. Super dirty stuff.

In the GT case, It frankly would put you at risk of a hang fire, squib, or pierced primers. All three probably only a couple tenths of a grain apart. Very little safety margin.

Better plan would be to simply start practicing with your go-to load for “barrel break in.” Don’t sweat the chrono numbers until you’re a few days of shooting into your new barrel.

As for getting the firing pin “bushed” it totally depends on how your action treats small rifle primers. If you start getting excess primer flow into the firing pin channel, it can put you at risk of pierced primers at relatively low pressures.

No way to tell until you start shooting and seeing what your primers look like. Chances are you’ll be fine with your defiance action. And if you are using thicker primer cup primers, it’s almost a non issue.

Hope you enjoy your new rifle. It’s a really capable cartridge
 
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